Breast cancer
The most common cancer in women worldwide, arising from the milk ducts or lobules. Screening and modern treatment mean most women diagnosed early are cured.
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About 2.3 million new cases a year; roughly 1 in 8 women in high-income countries during their lifetime. Men can also be affected (about 1%).
What happens in the body
Most cancers are hormone-receptor positive (driven by oestrogen/progesterone); about 15–20% over-express HER2; triple-negative cancers lack all three.
Causes
- Accumulated genetic changes in breast cells
Risk factors
- Female sex and age
- BRCA1/BRCA2 and other inherited mutations
- Family history
- Early periods, late menopause, no pregnancies or first pregnancy after 30
- Hormone replacement therapy
- Alcohol
- Obesity after menopause
- Dense breasts
- Previous chest radiotherapy
Symptoms
- New lump or thickening in the breast or armpit
- Change in breast size or shape
- Skin dimpling or 'orange peel'
- Nipple inversion, discharge or rash
- Often no symptoms — found on screening
Diagnosis — tests and examinations
- Triple assessment: clinical examination, imaging (mammography, ultrasound, MRI) and core biopsy
- Receptor testing (ER, PR, HER2)
- Staging scans for larger tumours
- Genetic testing when indicated
Treatment
Medicines and medical treatment
- Hormone therapy (tamoxifen, aromatase inhibitors) for 5–10 years
- Chemotherapy before or after surgery
- HER2-targeted therapy (trastuzumab, pertuzumab, T-DXd)
- CDK4/6 inhibitors, PARP inhibitors (BRCA), immunotherapy for triple-negative disease
- Radiotherapy after breast-conserving surgery
Operations and procedures
- Wide local excision (lumpectomy)
- Mastectomy with optional reconstruction
- Sentinel lymph node biopsy or axillary clearance
- Risk-reducing mastectomy and salpingo-oophorectomy for mutation carriers
Self-care, home remedies and lifestyle
- Know what is normal for your breasts
- Physical activity, limit alcohol, healthy weight
- Lymphoedema exercises after surgery
Possible complications
- Spread to bone, liver, lungs and brain
- Lymphoedema
- Treatment side effects (menopausal symptoms, heart effects)
Prevention
- Screening mammography (typically every 2–3 years from 40–50)
- Risk-reducing medicines or surgery for high-risk women
- Breastfeeding, activity, limiting alcohol
Outlook
Five-year survival exceeds 90% for early-stage disease.
When to see a doctor
See a doctor promptly for any new breast lump or change.
Sources and further reading
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